Summary of variable-displacement engine project

Conference · Thu Sep 01 04:00:00 EDT 1977

OSTI ID:7208843

Robinson, C W

A variable-displacement, five-cylinder, spark-ignition research engine has been designed, fabricated, and tested. This design reduces partial-load fuel consumption by reducing throttling and friction losses. Power is controlled by changing the piston stroke rather than by throttling, except at idle and very low power levels. A linkage arrangement allows for continuous changes in stroke and therefore in engine displacement. The prototype has a bore of 3.375 inches, and stroke varies from 1 to 4/sup 1///sub 4/ inches as displacement varies from 43 to 190 cubic inches. The linkage concept is such that clearance volume can be changed in proportion to the stroke. Thus nearly constant compression ratio can be achieved, or (by proper selection of the linkage dimensions) compression ratio can be tailored to optimize the design. During design, dynamic analyses of various configurations of the engine were done to determine member loads and unbalanced forces and to assist in selecting the linkage configuration. Dynamic analysis was also used to select five as the number of cylinders, to determine the firing order to reduce engine vibration, and to compare vibration with that of a conventional engine. An engineering model of the engine fluid dynamics was also developed and was used to predict engine performance, to select cam contours, and to optimize cam timing.

• Research Organization: Sandia Labs., Albuquerque, N.Mex. (USA)
• DOE Contract Number: EY-76-C-04-0789
• OSTI ID: 7208843
• Report Number(s): SAND-77-8270; CONF-771037-1
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330101 -- Internal Combustion Engines-- Spark-Ignition
330603* -- Vehicle Design Factors-- Engine System
AUTOMOBILES
COMPRESSION
CONTROL SYSTEMS
DESIGN
ENGINES
FABRICATION
FLUID MECHANICS
FRICTION
FUEL ECONOMY
INTERNAL COMBUSTION ENGINES
MATHEMATICAL MODELS
MECHANICAL VIBRATIONS
MECHANICS
SPARK IGNITION ENGINES
TESTING
VEHICLES